One person has tested positive for the new Omicron variant of the coronavirus on the French Indian Ocean island of La Reunion and six of his contacts are being tested, the government said on Tuesday.

Official researcher Dr. Patrick Mavingui said the person was a 53-year old man who had travelled to Mozambique and made a stop-over in South Africa.

The patient, who returned to La Reunion some two weeks ago, is in isolation, Mavingui told local French media.

French government spokesman Gabriel Attal Attal confirmed the case. "Six of his contacts have been put in isolation, three coming from his family circle and three from his professional circle," he told Europe 1 radio.

Omicron, first reported in southern Africa and which the World Health Organization (WHO) said risks infection surges, has triggered global alarm, with border closures casting a shadow over a nascent economic recovery.

Attal said results concerning eight possible cases of the variant across France were expected in coming hours.

Health ministry data showed on Monday that France had registered its biggest jump in coronavirus-related hospital admissions since the spring. 

The number in intensive care units (ICUs) with COVID-19 jumped by 117 to 1,749 people, the biggest rise since March-April.